PX4 Pixhawk Toolbox - External Mode - Model not sending data

I am working with a Ubuntu System, 2016b Matlab, the most current toolbox, and the firmware version 1.4. I am struggling to get readouts from my external mode model. I have gotten the example external mode models to work perfectly, I even have a modified external mode model working. My model uses a Uorb Function call system which rate transition blocks to my controller so that all the signals are synchronized. I have two questions:

1.) I use the control_state uorb topic, why should I assume (or matlab assumes) that the various data streams from this one topic are asynchronous?

2.) Where can I find good documentation on what rates I should use? Should I use rate transition blocks with the uOrb Function call?